The above image is published here under the following terms:

License

This image was published under the terms of the Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) license. It may be copied, redistributed, or modified as long as attribution to the original source is given. It must be redistributed under an identical license.

Owner/Creator

User:Krishprakash24gmail at Wikimedia Commons

Source

File:Ajax loader metal 512.gif at Wikimedia Commons

Rationale

To indicate that a page element is loading.